20603 has 4 divisors (see below), whose sum is σ = 22488. Its totient is φ = 18720.

The previous prime is 20599. The next prime is 20611. The reversal of 20603 is 30602.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20603 - 2² = 20599 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (11), and also a Moran number because the ratio is a prime number: 1873 = 20603 / (2 + 0 + 6 + 0 + 3).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20663) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 926 + ... + 947.

It is an arithmetic number, because the mean of its divisors is an integer number (5622).

2²⁰⁶⁰³ is an apocalyptic number.

20603 is a deficient number, since it is larger than the sum of its proper divisors (1885).

20603 is a wasteful number, since it uses less digits than its factorization.

20603 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1884.

The product of its (nonzero) digits is 36, while the sum is 11.

The square root of 20603 is about 143.5374515588. The cubic root of 20603 is about 27.4142785260.

Subtracting 20603 from its reverse (30602), we obtain a palindrome (9999).

The spelling of 20603 in words is "twenty thousand, six hundred three".